1. Field of the Invention
The present invention relates, in general, to reciprocating compressors and, more particularly, to a valve assembly for the reciprocating compressors, elements of which are easily and simply assembled into a single body, and which reduces operational impact and noise caused by an operation of a reed valve, thus allowing a silent operation of the reciprocating compressors.
2. Description of the Related Art
As well known to those skilled in the art, a reciprocating compressor includes a plurality of elements, that is, a stator, a rotor, a crankshaft, a cylinder, a piston, and a cylinder head, which are hermetically housed in a hermetic casing. The stator and the rotor are installed in the hermetic casing such that the stator is immobile, while the rotor is rotatable. The crankshaft axially and fixedly penetrates through the rotor to rotate along with the rotor in response to an electromagnetic action between the stator and the rotor when the compressor is electrically turned on. The cylinder defines a chamber therein to suck and compress a gas in the chamber, while the piston is received in the cylinder so as to perform a rectilinear reciprocating motion in the cylinder, in response to a rotation of the crankshaft. The cylinder head covers a top of the cylinder. In an operation of the reciprocating compressor, the piston rectilinearly reciprocates in the cylinder in response to the rotation of the crankshaft, thus sucking a gas into the cylinder inside the hermetic casing, and compressing the gas, prior to discharging the compressed gas under high pressure from the cylinder to the outside of the hermetic casing. The reciprocating compressor having the above-mentioned construction is preferably used in a refrigeration system, such as a refrigerator or an air conditioner, to compress a gas refrigerant under low pressure to make the gas refrigerant under high pressure.
In the reciprocating compressor, a valve assembly is interposed between the cylinder and the cylinder head to control low-pressure gas suction into the cylinder inside the hermetic casing and high-pressure gas exhaust from the cylinder to the outside of the hermetic casing, during the operation of the compressor.
The conventional valve assembly for reciprocating compressors includes an exhaust valve unit having a reed valve, a stopper, and a keeper. The reed valve controls the gas exhaust from the cylinder to the outside of the hermetic casing, while the stopper limits an opening ratio of the reed valve within a predetermined range. The keeper supports the stopper. The reed valve, stopper and the keeper of the exhaust valve unit are sequentially assembled on an exhaust hole plate which has both a suction hole and an exhaust hole. The exhaust hole plate having the exhaust valve unit is set together with a suction valve plate integrally having a suction valve, at a position between the cylinder and the cylinder head by use of a plurality of bolts.
When the piston is moved from a lower dead center to an upper dead center in the cylinder, the gas is compressed in the cylinder. Pressure of the compressed gas is thus applied to the exhaust hole, so that a free end of the reed valve is elastically bent along with the stopper toward the cylinder head, thereby opening the exhaust hole. The compressed gas under high pressure is discharged from the cylinder to the outside of the hermetic casing through the cylinder head and the open exhaust hole. When the piston is moved from the upper dead center to the lower dead center in the cylinder, the reed valve elastically doses the exhaust hole, due to a restoring force of both the stopper and the reed valve, and, at the same time, the suction valve of the suction valve plate is opened to suck the gas under low pressure into the cylinder through the open suction hole and the cylinder head.
However, the conventional valve assembly for reciprocating compressors is problematic, as follows. That is, in the conventional valve assembly, the reed valve to control the exhaust hole, the stopper to limit the opening ratio of the reed valve within the predetermined range, and the keeper to support the stopper are separately produced, and are sequentially assembled on the exhaust hole plate. Therefore, it is necessary to sequentially assemble the reed valve, stopper and the keeper on the exhaust hole plate, prior to setting the exhaust hole plate between the cylinder and the cylinder head by use of a plurality of bolts. Excessive time is consumed while assembling the reed valve, stopper and the keeper into the valve assembly.
In the conventional valve assembly for reciprocating compressors, a first end of the reed valve forms a junction end at which the reed valve is mounted to the exhaust hole plate, and a second end of the reed valve forms the free end which is elastically bent from the exhaust hole plate toward the cylinder head, due to an exhaust pressure applied thereto. Therefore, the free end of the reed valve repeatedly strikes against the stopper and the exhaust hole plate during the rectilinear reciprocating motion of the piston in the cylinder, thus generating operational impact and noise. In addition, the reed valve vibrates at the free end thereof, thus generating high-frequency noise to prevent a silent operation of the reciprocating compressors.